The present invention relates to a pharmaceutical composition for topical administration suitable for the prophylaxis and treatment of herpesvirus infections. The pharmaceutical composition comprises a combination of an antiviral agent and an antiinflammatory agent and can preferably be used for the treatment of recurrent herpesvirus infections.
Herpesvirus infections in humans can be caused by different human herpesviruses, the most common being herpes simplex virus and varicella-zoster virus. There are also many animal herpesviruses.
Following a primary infection with herpes simplex virus or varicella-zoster virus, the virus establishes latency in the sensory nerve cells for the rest of the patient""s life and can subsequently be reactivated repeatedly. Following a reactivation in the nerve cell, the virus is transported through the nerves to the skin and subsequently a lesion develops. One characteristic of herpesvirus infection is the inflammation which follows immediately upon an outbreak of virus replication. The inflammation contributes to all symptoms associated with herpesvirus recurrence including redness, swelling, itching and pain as well as lesions.
Herpes simplex viruses can be divided into two serotypes, HSV type 1 (HSV-1) and type 2 (HSV-2), the clinical manifestations of which range from benign self-limiting orofacial and genital infections to potentially life threatening conditions such as encephalitis and generalized neonatal infections.
Oral-facial HSV infections are primarily caused by HSV-1. Following a primary infection in childhood the virus becomes latent. After reactivation a recurrent oral-facial HSV infection develops, which is more commonly known as a cold sore. About half of the patients experience prodromal symptoms such as pain, burning or itching at the site of the subsequent lesions. The condition is generally rapidly self-limiting and a typical episode will heal in around 10 days from the first symptoms. Viral replication in the lip is initiated early and maximum virus load is attained 24 hours after the onset of the reactivation. The virus concentration is then dramatically reduced and typically virus cannot be isolated 70-80 hours after the onset.
The clinical presentation of genital HSV infections is similar to the oral-facial infections with some important exceptions. Genital HSV infections are most often caused by HSV-2 and following the primary infection the virus will latently infect sensory or autonomic ganglions. Reactivation will produce the local recurrent lesions on or near the genitals that are characteristic of the herpes infection.
A primary infection with varicella-zoster virus (VZV) causes chicken-pox. Like HSV, VZV becomes latent following the primary infection and can be activated as herpes zoster later on in life. Zoster usually results in skin rash and intensive acute pain. In 30% of the patients, the pain can be prolonged and continue for weeks or months after the rash has cleared up.
HSV and VZV may, in addition to mucous or cutaneous manifestations, also cause keratitis in the eyes. This condition is also recurrent and may cause blindness.
There are a number of antiviral agents which are active against the human herpesviruses. There has, however, so far been limited clinical success in the treatment of recurrent herpesvirus infections.
Foscarnet, that is the hexahydrate of the trisodium salt of phosphonoformic acid or sodium phosphonoformate hexahydrate, and acyclovir are well-known antiviral compounds, which as topical formulations have been extensively tested against recurrent herpes simplex virus infections in clinical trials with only a moderate degree of success. Acyclovir has, in addition, been tested as an oral formulation against recurrent HSV infections with significant but limited clinical effect if used after the appearance of symptoms. As a result of such a treatment the healing time will be shortened by no more than approximately one day. The inhibitory effect of foscarnet, as well as that of acyclovir, against herpes viruses in vitro is, however, high.
Standard-dose acyclovir shows little effect against VZV infections in the clinic. High-dose acyclovir shows significant but limited effect on zoster lesions if treatment is initiated within 72 hours from the appearance of the first symptoms.
Other antiviral substances, which have been used topically and which exhibit an inhibitory effect against HSV in vitro, are for example adenine arabinoside (ara-A, vidarabine), arabinosyladenine-monophosphate (ara-AMP), lobucavir (bishydroxymethylcyclobutylguanine, BHCG), brivudine (bromovinyldeoxyuridine, BVDU), desciclovir, famciclovir, cidofovir (HPMPC, GS504), idoxuridine, netivudine (zonavir, BW882C87), penciclovir, PAA (phosphonoacetate), PFA (phosphonoformate), sorivudine (brovavir, BV-araU), trifluridin (trifluorothymidine, TFT), tromantadine, valacyclovir, virend, 1-docosanol (lidakol), 348U87, 2242 (2-amino-7-(1,3-dihydroxy-2-propoxymethyl)purine), HOE 961, civamide (capsaicin), PMEA (9-(2-phosphonylmethoxyethyl)adenine), peptide T, BILD 1263, CRT.
Clinical primary infections with human herpes simplex viruses differ in a number of important aspects from subsequently reactivated infections. The viral shedding period is longer in the primary infection (about 10 days in labial and 3 weeks in genital infection) compared with reactivated infection (3-4 days for both labial and genital infections). Following termination of the viral shedding period in primary infections the lesion will heal in a few days while in the case of reactivated infections, the inflammation continues after viral replication has ceased and the clinical symptoms will remain for another week.
Obviously a reduction of virus multiplication in itself will not substantially alter the clinical course of a recurrent herpes infection. It is, therefore, not surprising that antiviral drugs when tested in clinical trials show a more substantial effect against a primary infection as compared with reactivated infections, such as recurrent herpes labialis or genitalis. Because of the rapid self-limiting nature of the virus shedding period in recurrent HSV infection the improvement of only one day healing time obtained in clinical trials with antiviral drugs is not surprising.
Different antiinflammatory agents have been tested to treat the inflammation that accompanies the recurrent infection, but only with limited success. Traditionally, inflammatory conditions in the eye, such as keratitis, have been treated with steroids. Even though this type of compounds is known to potentially promote herpesvirus replication steroids have been used in severe cases, for instance to save the patients vision. This practice has been controversial.
In summary, there has been little clinical success in the treatment of recurrent herpesvirus infections even with the most potent antiviral drugs. There is, thus, a great need for effective drugs and methods of treatment for recurrent herpes infections.
AU 636 255 refers to topical treatment of for instance herpes simplex infections by means of a composition comprising an antiviral pentosan polysulphate and an antiinflammatory or antioxidant drug. The antiinflanmmatory drugs are different salicylates or bufexamal, that is NSAIDs.
U.S. Pat. No. 3,317,384 discloses a combination of a glucocorticoid and an antiviral nucleoside, ara-C or ara-A or analogues thereof, for topical pharmaceutical applications, mainly for ocular administration. The systemic toxicity of the antiviral compounds is too high to allow for an application to the skin or mucous membrane.
Power, W. J., et al., British Journal of Ophthalmology 1992; 76:711-713, reports a treatment of patients with disciform keratitis with either 3% acyclovir ointment and 0.1% betamethasone drops or acyclovir ointment and matching placebo. It was concluded that the healing time as well as other clinical parameters improved more favourably in the combination treatment group.
On the other hand McGill, J.: Herpes zoster ocular infection, Scand J Infect Dis Suppl 1985; 47: 85-8 reports an analysis of patients with herpes zoster ocular infection carried out to determine the effect of treatment with either topical acyclovir, topical steroid or a combination of both. It was found that acyclovir was superior to steroids and to the combination.
It has now surprisingly been found that recurrent herpesvirus infections can be treated by topical administration of a combination of a topically acceptable antiviral substance and an antiinflammatory glucocorticoid.
The invention relates to a pharmaceutical composition for topical administration comprising a combination of a topically acceptable antiviral substance and an antiinflammatory glucocorticoid in a pharmaceutically acceptable carrier.
Antiviral substances suitable for the purposes of the present invention are topically acceptable antiviral compounds which in addition to being specific inhibitors of herpesvirus multiplication, also are active after topical administration and in addition pharmaceutically acceptable for topical administration. This means that the toxicity of the antivirals must be sufficiently low to allow for a continuous contact with the human body and in particular with the skin and mucous membranes.
Antiviral substances can be selected from the group comprising compounds acting on viral DNA polymerase, such as nucleoside analogues after phosphorylation to their triphosphate forms; phosphonoformic and phosphonoacetic acids and their analogues; and other antiviral compounds having a different mechanism of action. As examples of antiviral substances which can be used in the combination of the invention can be mentioned acyclovir (ACV), ACV-phosphonate, brivudine (bromovinyldeoxyuridine, BVDU), carbocyclic BVDU, buciclovir, CDG (carbocyclic 2xe2x80x2-deoxyguanosine), cidofovir (HPMPC, GS504), cyclic HPMPC, desciclovir, edoxudine, famciclovir, ganciclovir (GCV), GCV-phosphonate, genivir (DIP-253), H2G (9-[4-hydroxy-2-(hydroxymethyl)butyl]guanine), HPMPA, lobucavir (bishydroxymethylcyclobutylguanine, BHCG), netivudine (zonavir, BW882C87), penciclovir, PMEA (9-(2-phosphonylmethoxy-ethyl)adenine), PMEDAP, sorivudine (brovavir, BV-araU), valacyclovir, 2242 (2-amino-7-(1,3-dihydroxy-2-propoxymethyl)purine), HOE 602, HOE 961; BPFA (batyl-PFA), PAA (phosphonoacetate), PFA (phosphonoformate); arildone, amantadine, BILD 1263, civamide (capsaicin), CRT, ISIS 2922, peptide T, tromantadine, virend, 1-docosanol (lidakol) and 348U87 (2-acetylpyridine-5-[2-chloro-anilino-thiocarbonyl]-thiocarbonohydrazone).
Preferred antiviral substances are those with specific antiviral activity such as herpes specific nucleoside analogues which are preferentially phosphorylated in virus-infected cells and have very low or non-existent incorporation into cellular DNA as well as other compounds with specific antiviral activity. Acyclovir, for instance, has a selectivity ratio for the inhibitory activity against HSV-1 in vitro of about 2000. Among said preferred substances can in addition to acyclovir be mentioned brivudine, cidofovir, desciclovir, famciclovir, ganciclovir, HOE 961, lobucavir, netivudine, penciclovir, PMEA, sorivudine, valacyclovir, 2242, BPFA, PFA, PAA.
Especially preferred are foscarnet and acyclovir.
PFA, as used in this specification and claims, refers in addition to foscarnet, that is the hexahydrate of the trisodium salt of phosphonoformaic acid, also to other pharmaceutically acceptable salts, esters or other derivatives of phosphonoformic acid in hydrated or non hydrated form. In the same way the stated antiviral substances also refer to salts, esters and other derivatives thereof, whenever applicable.
Some topically active antiviral substances, such as the nucleoside analogues idoxuridine and trifluorothymidine, adenine arabinoside (ara-A, vidarabine) and arabinosyladenine-monophosphate (ara-AMP), which can be used for the treatment of herpetic conditions in the eye are not contemplated within the scope of this invention as having too high a toxicity for application to the skin and mucous membrane. This toxicity is due to the lack of antiviral specificity, that is said compounds are phosphorylated in uninfected as well as infected cells and incorporated into cellular DNA.
It could be of advantage to utilize two or more antivirals or to combine the antiviral with an adjuvant or other additive in order to increase the effect on the herpesvirus to be treated, for instance in cases of resistance developed to a particular antiviral substance.
The antiinflammatory glucocorticoid suitable for the purposes of the present invention can be a naturally occurring or a synthetic topical glucocorticoid that is glucocorticosteroid. The glucocorticoids can be selected from any of the Group I-III glucocorticoids, according to a classification system for topical glucocorticoids used in the Nordic countries, corresponding to less potent, low or moderately potent glucocorticoids. Examples of glucocorticosteroids are alclometasone, amicinonide, beclomethasone, betamethasone, budesonide, ciclesonide, clobetasone, clocortolone, cloprednol, cortison, desonide, desoximethasone, dexamethasone, diflorosane, diflucortolone, difluprednate, fludrocortisone, fludroxycortid, flumethasone, flunisolide, fluocinolone acetonide, fluocinonide, fluocortin, fluocortolone, fluprednidene, fluticasone, halcinonide, halobetasol, halometasone, hydrocortisone, methylprednisolone, mometasone, paramethasone, prednisolone, prednicarbate, prednisone, prednylidene, rofleponide, tipredane and triamcinolone and their esters, salts and solvates, that is hydrates, where applicable.
Preferred glucocorticoids are hydrocortisone, alclometasone, desonide, fluprednidene, flumethasone, hydrocortisone butyrate, clobetasone, triamcinolone acetonide, betamethasone, budesonide, desoximethasone, diflorosane, fluocinolone, fluocortolone, fluticasone, methylprednisolone aceponate, mometasone and rofleponide.
A preferred embodiment of the invention is a pharmaceutical composition comprising foscarnet and hydrocortisone; in another embodiment the pharmaceutical compositon comprises foscarnet and budesonide.
Still another preferred embodiment of the invention is a pharmaceutical composition comprising acyclovir and hydrocortisone; in another embodiment the pharmaceutical composition comprises acyclovir and fluticasone.
The carrier system should be stable and pharmaceutically and cosmetically acceptable. It should also enable incorporation of sufficient amounts of the active ingredients to give the proper penetration characteristics. In addition to conventional ingredients in creams, lotions, gels or ointments, compositions based on phospholipids, including sphingolipids can be advantageous.
A pharmaceutical composition of the invention can be used for the prophylaxis and/or treatment of herpesvirus infections in mammals including man. In a preferred embodiment the composition is used for the treatment of recurrent herpesvirus infections. The curative treatment of recurrent infection should take place during the virus replication, preferably from the first appearance of prodromal symptoms and for a period of 3-4 days at least. It might be of advantage to apply the formulation during the whole episode, every second hour or ad lib. Lesions should be treated the same way. The frequency of application will be of the order of 1-10 applications per day, preferably every 8 hour, until healing is completed. Prophylactic treatment could be an alternative in patients with regularly recurrent disease. In this case the formulation should be applied to the area where a recurrence is expected before the appearance of the first symptoms.
The compositions of the invention can be used to treat all types of herpesvirus, as well as other viruses, which are inhibited by the antiviral substance and which replicate in the skin or the mucous membrane. As exemples of said viruses can be mentioned HSV-1, HSV-2 and VZV.
The pharmaceutical compositions for topical administration according to the present invention are preferably creams, lotions, gels, ointments or drops. The pharmaceutical compositions can be incorporated into plasters or patches to be applied to the skin of a patient to be treated for herpes infections or into pens or sticks for application to the skin or mucous membranes.
Topical administration refers in this context to dermal or mucosal administration to the skin or mucous membrane.
Due to the herpesvirus-stimulating effects of glucocorticoids, care must be taken to define the optimal dose of the respective components. Too high a dose of the glucocorticoid might stimulate virus multiplication to an extent that can not be inhibited by the antiviral substance. With too low a dose the desired reduction of the symptoms of inflammation might not be achieved.
The mutual relationship between the two active substances will be different for different combinations of substances. The relative amount of the antiviral substance in a pharmaceutical composition according to the present invention can be within the range of 0.1-10% (w/w), preferably 1-5% (w/w). The antiinflammatory glucocorticoid concentration can be within the range of 0.005-3% (w/w) depending on the potency of the respective compound. A pharmaceutical composition containing a combination of foscarnet and hydrocortisone could preferably comprise 0.3-3% foscarnet and 0.25-1% hydrocortisone. A corresponding composition containing acyclovir and hydrocortisone preferably comprises 1-5% acyclovir and 0.25-1% hydrocortisone.
In another aspect the invention also refers to the use of a combination of a topically acceptable antiviral substance and an antiinflammatory glucocorticoid for the manufacture of a medicament for topical treatment of recurrent herpesvirus infections in mammals including man.
In another aspect, the present invention refers to a method of prophylactic and/or curative treatment of herpesvirus infections of the skin or mucous membranes in mammals including man comprising topical administration, in combination or in sequence, of a therapeutically effective dose of a topically acceptable antiviral substance and of an antiinflammatory glucocorticoid.
In yet another aspect the pharmaceutical compositions of the present invention can also be used as a cosmetic composition to improve the appearance of a human suffering from an oral-facial HSV infection by application of an effective amount of said compositions to the lesions or rash.
The topical administration of the pharmaceutical compositions of the present invention have resulted in a significantly better pharmacological effect in the treatment of recurrent herpes infections than the administration of conventional topical compositions comprising an antiviral compound as the only active substance. This has been determined in biological tests by means of a new animal model described below.